The hypnotic state is caused by the hypnotist distracting the conscious mind in order to communicate directly with the sub-conscious mind.
Around 98% of our actions, thoughts and feelings come from the sub-conscious. We don't even think about it, it just happens. Think about picking up a pen. You don't consciously direct your mind to move your arms and fingers to do this. You have the thought and your body responds automatically. At some point in your life you've learned to do this and can now do it at will.
Being able to effortlessly pick up a pen is a useful pattern. However, the sub-conscious also stores bad habits, gremlin voices, and other unhelpful patterns that we adopt over time.
As you will have learned useful patterns, you will also have learned unhelpful patterns, or even patterns that were useful at some time but aren't appropriate now. You can use hypnosis to erase unhelpful patterns and input suggestions of positive thoughts and actions that will take their place. If your thinking is different, then your actions will also be different.
In short, hypnosis facilitates rapid and permanent change.
If you've seen a hypnosis stage show, you'll probably have witnessed people doing some pretty daft stuff - like happily eating an onion while thinking it's an apple. Although hypnosis can be used to get people to do things they wouldn't normally, you cannot be persuaded to do anything that's against your moral or ethical beliefs.
Hypnosis when used in a therapeutic or self development environment 'turns down the volume' on negative thoughts while increasing the volume on the positive things. The simple fact of being in a hypnotic state with no further input is a relaxing and rejuvenating experience in itself as the body and mind become completely still.
What you can use hypnosis for
De-stressing, feeling relaxed and calm, building confidence and self-esteem, stopping smoking, losing weight, gaining weight, increased performance, being more assertive, motivation, overcoming relationship issues, fears and phobias and basically anything else that you want to do or feel differently about.

"'I didn't realise until today how powerful my work with Clare had been until I arrived at an important meeting feeling calm, relaxed and ready to do business'"
SG